1. Field of the Invention
The present invention relates to an image forming apparatus for copying machine and printers and the like.
2. Description of the Related Art
A requirement of the image forming apparatus used in copying machines and printers and the like is the periodic replacement, inspection and adjustment of consumable components such as the photoconductive drum used as a carrier for an electrostatic latent image and the toner accommodated in the developing unit that develops the electrostatic latent image formed on the surface of the photoconductive drum, the aforesaid servicing being performed by a specialist technician. Accordingly, it is extremely troublesome so send for the service technician each time servicing is required. Recent efforts to simplify replacement, inspection and adjustment of each component of the device have led to image forming apparatus wherein the photoconductive drum required for image formation and the developing means for developing the electrostatic latent image formed on the surface of said photoconductive drum in accordance with the image information have been integrated into a single unit that is removable from the image forming apparatus.
On the other hand, the aforesaid image forming apparatus require precise maintenance of the positional relationships of paper supplying devices such as registration rollers to regulate the timing transported transfer material and the processing means such the photoconductive drum in order to align the leading edge of the toner image formed on the surface of the photoconductive drum with the leading edge of the transfer material transported from the paper supplying device so as to assure an accurate transfer. Thus, conventional image forming apparatus are constructed with a frame that is capable of being pulled out from the apparatus, said frame supporting removable processing means such as the photoconductive drum and a pair of registration rollers (as disclosed in Japanese Patent Application No. 57-139764).
Although inspection and replacement of the processing means such as the photoconductive drum are simplified and adjustment of the positional relationship of the processing means and paper supplying means is also simplified in the aforesaid image forming apparatus, there are nevertheless certain inherent disadvantages which are described hereinafter.
That is, because a pair of registration rollers is supported on the frame, a sheet feed error may occur when the transfer material is gripped between said pair of registration rollers, whereupon in an extremely inconvenient operation the entire frame must be pulled from the apparatus and the registration rollers manually rotated so as to extract the jammed sheet from therebetween.
Further, when the frame is installed in the apparatus, a drive force supplied by a drive motor mounted in the apparatus is received at one location, and said drive force is then transmitted to the photoconductive drum and the developing roller of the developing means. Thus, problems arise when a load is applied to the developing roller of the developing means and the like, because the variation induced by said load is directly transmitted to the photoconductive drum and dislocation is produced by the rotation of said photoconductive drum.